DESCRIPTION: Opioid dependence is a serious and increasingly pervasive problem. Opioid dependent individuals are at significantly increased risk for a wide range of physical and psychological problems including HIV and STIs. Extended-release naltrexone (XR-NTX) is an effective treatment for opioid dependence, but it requires that opioid-dependent individuals be completely opioid-free prior to its initiation to avoid precipitated withdrawal. The great majorityof individuals attempting to cease opioid use will relapse before initiation of XR-NTX because of opioid withdrawal symptoms during detoxification. Distress Tolerance (DT) focused psychosocial interventions are well suited to address the clinical phenomena experienced by individuals withdrawing from opioids. The present proposal is to develop a DT intervention to improve detoxification outcomes and an active comparison intervention targeting HIV and STI (HIV/STI) risk behavior. The DT intervention will be adapted from Acceptance and Commitment Therapy (ACT). The HIV/STI risk behavior intervention will target behaviors that put patients at risk for HIV and STIs including unprotected sex and needle sharing, as well as promoting regular HIV testing. Both interventions will be delivered through a telehealth videoconferencing system. If the HIV/STI intervention is found to result in reduced HIV/STI risk behavior and more frequent HIV testing, relative to the DT intervention, we will incorporate its components into the DT intervention prior to launching a large- scale clinical trial. The long-term objective of this research program is to improve substance use and HIV/STI outcomes for opioid dependent individuals attempting to cease opioid use. In Phase 1 of the proposed project, we will develop and pilot a DT intervention for individuals transitioning to XR-NTX and a time-matched HIV/STI risk reduction comparison intervention; both will be developed using an iterative process of piloting and modification based on data collected from pilot participants. In Phase 2, opioid dependent individuals transitioning to XR-NTX will be randomly assigned to DT, HIV/STI, or Treatment-As-Usual. All patients will receive medication assisted detoxification from the study recruitment site. We expect that, as a result of this project, we will have developed a well-specified and novel DT intervention tailored to meet the needs of opioid dependent patients transitioning to XR-NTX, the efficacy of which can be further tested in future Stage II randomized controlled trials. If found to be efficacious, this intervention will serve as an effectve means of facilitating detoxification and opioid antagonist initiation, reducing the individual and societal burden due to opioid dependence.